JEE Advance - Chemistry (2024 - Paper 2 Online - No. 4)
The species formed on fluorination of phosphorus pentachloride in a polar organic solvent are
$\left[\mathrm{PF}_4\right]^{+}\left[\mathrm{PF}_6\right]^{-}$and $\left[\mathrm{PCl}_4\right]^{+}\left[\mathrm{PF}_6\right]^{-}$
$\left[\mathrm{PCl}_4\right]^{+}\left[\mathrm{PCl}_4 \mathrm{~F}_2\right]^{-}$and $\left[\mathrm{PCl}_4\right]^{+}\left[\mathrm{PF}_6\right]^{-}$
$\mathrm{PF}_3$ and $\mathrm{PCl}_3$
$\mathrm{PF}_5$ and $\mathrm{PCl}_3$
Explanation
When $ \text{PCl}_5 $ is fluorinated in a polar organic solvent, it forms ionic isomers. The formation of these ionic species can be understood as follows:
- $ \text{PCl}_5 $ in a polar organic solvent can dissociate into ionic forms, such as $ \left[\text{PCl}_4\right]^+ $ and $ \left[\text{PCl}_6\right]^- $.
- Upon fluorination, $ \text{PCl}_5 $ can be converted into $ \left[\text{PF}_6\right]^- $ and $ \left[\text{PCl}_4\right]^+ $.
- Further fluorination can lead to the formation of mixed ionic compounds where $ \text{PCl}_5 $ can form isomers like $ \left[\text{PCl}_4\right]^+ \left[\text{PCl}_4 \text{F}_2\right]^- $.
The two ionic isomers formed are:
- $ \left[\text{PCl}_4\right]^+ \left[\text{PCl}_4 \text{F}_2\right]^- $, which are colorless crystals.
- $ \left[\text{PCl}_4\right]^+ \left[\text{PF}_6\right]^- $, which are white crystals.
Hence, the ionic isomers formed when $ \text{PCl}_5 $ is fluorinated in a polar organic solvent are :
Option B : $ \left[\text{PCl}_4\right]^+ \left[\text{PCl}_4 \text{F}_2\right]^- $ and $ \left[\text{PCl}_4\right]^+ \left[\text{PF}_6\right]^- $Comments (0)
